In a retransmission communication system using a hybrid automatic repeat request (H-ARQ) method, a receiver may issue a request for the retransmission of data to a transmitter by transmitting a negative acknowledgement message if data received from the transmitter is erroneous. The transmitter may retransmit the same data as the data (hereinafter referred to as the initially-transmitted data) initially transmitted by the transmitter to the receiver upon receiving the negative acknowledgement message.
Data transmitted by the transmitter may include a bit string encoded using a predetermined encoding method. The transmitter retransmits data (hereinafter referred to as the retransmitted data) having the same bit string as the initially-transmitted data to the receiver upon receiving the negative acknowledgement message. The receiver combines the initially-transmitted data and the retransmitted data, decodes data obtained by the combination, and determines whether the decoded data is erroneous.
However, if the receiver simply combines the initially-transmitted data and the retransmitted data without preprocessing a bit string of the initially-transmitted data and a bit string of the retransmitted data, the speed of processing or the reliability of decoding may decrease due to an increase in the coding rate of data obtained by the combination.